elfman
Part of things
Posts: 399
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Jul 16, 2020 21:26:37 GMT
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For the way most people normally drive there is a pretty good correlation between torque and perceived acceleration and power and top speed, the reality though is if you are preparred to always keep the engine around the max power rpm this is where you will get the fastest acceleration and top speed. Can't wait to see this built. Yes that's true , I remember when people first started to put bike engines in to Lotus 7 , Westfields and the like... many said they would never work because they did not have much Torque.... They soon had to eat there words.... once you get the engine in its rev band its out and out power that gives you acceleration... One old racer once said Torque is for lazy buggers or people who cant drive properly and miss gears.. But it is handy for towing... |
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Darkspeed
Club Retro Rides Member
Posts: 4,869
Club RR Member Number: 39
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Jul 16, 2020 21:47:59 GMT
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You'll see way more detail soon as I load up more pics. Its a nicely built engine that's for sure! If the design and manufacture is anything like the C27A in the Strato's I look forward to seeing it in detail. Interesting note on the intake dimensions - My race Imp 998 that is over 100BHP/Litre only has 1" ports feeding 1.32" valves - As the Honda is the same cylinder capacity that 1" port has the ability to flow more than enough air. Be interesting to see what the seats and area behind the valve looks like. |
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Jul 16, 2020 23:03:23 GMT
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Very cool project.  About the gearbox, the Goldwing already has one, right? And it has reverse? So why not just bolt it up to a Lotus Elan diff? That would give you a good range of final drive options ( Ford English axle ), cheap LSD's, and flanges that match your halfshafts. Edit. Nevermind, you answered this question with the Sierra diff... |
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If your box does grenade itself then you might be able to use a Subaru gearbox. I know there's a kit you can buy from the states with reverse-cut CROWNwheels and pinions so VW beetles can run EJs sticking out of the back. Haven't worked through in my head whether that would get everything pointing in the right direction but might be an option I'm actually going to use a scooby (subaru) box however it's to be run reverse rotation. Which means the thrust within the helical gearsets is reversed. Its been done before with other on other boxes and works and looking through tech drawings of my subaru leone box i think i might just get away with it. But i plan to strip my spare box and look it over. There are thrust washers that i might be able to swap over etc. Update soon and you'll have more of an idea on what I'm planning. |
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I’m guessing it uses a 180mm ish dry clutch similar to the bmw K series motors then?
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It had a multi plate wet clutch (now in a box with many other parts)
Just discovered upon opening up my spare leone gearbox that the thrust surfaces opposite the main ones are not as big as I was hoping. Hmmmmmm.
I might take it to a local outfit, a crowd of boffins, and see what they think.
I looked up some formulas to work out thrust loads from helical gears but they made my eyes start to bleed and my brain began to hurt.
Maybe I'll just throw the box in and just wing it...
(see what i did there...)
Of course all this talk is useless without pics and I'm way behind on my uploads vs progress so I'll just shut up now.
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teaboy
Posted a lot
Make tea, not war.
Posts: 2,116
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Jul 17, 2020 10:36:51 GMT
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Yay wing it!
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cortina64
Part of things
Posts: 66 
Member is Online
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Jul 17, 2020 11:00:34 GMT
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So looking forward to seeing your updates, always enjoyed your threads.
What you have done already with the Imp has been first class, this takes it to another level.
Warren
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Jul 17, 2020 11:01:04 GMT
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Just fill the box with copperslip and banana skins and hope for the best?...
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Jul 17, 2020 17:23:07 GMT
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What’s stopping you using the Subaru gearbox upside down?
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Jul 17, 2020 17:28:33 GMT
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Aren't helical cut gears noisy if turning in the wrong direction?
I'm no expert, but I think I have read this somewhere (possibly from someone who also wasn't an expert!)
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teaboy
Posted a lot
Make tea, not war.
Posts: 2,116
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Jul 17, 2020 19:05:26 GMT
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What’s stopping you using the Subaru gearbox upside down? As he’s in New Zealand that would then make it the right way up... |
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Jul 17, 2020 21:21:24 GMT
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What’s stopping you using the Subaru gearbox upside down? Sadly that still wont change the input going into the box opposite to how it was designed. That's the problem. There's only two car engine manufacturers I can think of that have built engines that run backwards- Honda (up until about the 2000s) and the Chev Corvair. So finding boxes that are designed for that rotation direction (clockwise when looking at the back of the engine) leaves very little. Running the box upside down will only end up with the car having 5 gears in reverse. Oh and a huge gouge in the road from the previously top mounted starter motor A Corvair gearbox would work but they are only 4 speed, probably built like something from a tractor and not exactly common around here. I don't know that honda has ever built a longitudinal transaxle? Straight cut gears would solve the issues- but my money tree is a bit barren  I'm feeling confident that the 1st/2nd gear cluster might have a decent enough thrust surface from what I can deduce from the Haynes manual diagram. I have a plan on the other cluster but need to finish pulling it apart before I know more. Pics soon I promise :-) |
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Jul 17, 2020 21:26:39 GMT
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Aren't helical cut gears noisy if turning in the wrong direction? I'm no expert, but I think I have read this somewhere (possibly from someone who also wasn't an expert!) One way to find out. From what I have seen the profile is the same both side of the teeth. Plus its the unworn side so potentially its like a new box There has been a couple of people do a similar reverse input- one with an Audi transaxle in a fiat 850. He reported no issues or horrid noise at all. The other one was a 440ci powered race car- again no issues. Maybe longevity will suffer but I'll be stoked if I can just hoon this around a bit and I'll worry about if it makes it to a 50,000 mile service later.... |
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Jul 17, 2020 21:39:52 GMT
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Is it just the 1500 than runs reverse or the 1800 as well?
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Jul 17, 2020 21:42:31 GMT
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What about a Renault gearbox where the gearbox was in front of the engine,? That turned around would have you heading in the right direction. Renault 5 comes to mind, as well as the Renault Feugo .
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Last Edit: Jul 17, 2020 22:01:08 GMT by Deleted
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Jul 17, 2020 21:59:43 GMT
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Honda Vigor was fwd ,longitudinal engine
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scimjim
Club Retro Rides Member
Posts: 1,503
Club RR Member Number: 8
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Jul 17, 2020 22:03:47 GMT
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I imagine it’s impossible to find a gearbox and/or ridiculously expensive but didn’t the Corvair rotate the same way as the Honda and was rear engined/RWD?
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Jul 17, 2020 22:21:00 GMT
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If you are going to dump the built in gearbox, what is stopping you from running drop gears to reverse rotation of the output shaft? You could dump the crappy alternator drive at the same time. All you would still need to power would be the oil pump. Or..... Get a set of reverse rotation cams ground and change the idlers on the timing belts to the other side...
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Jul 17, 2020 22:31:21 GMT
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What about a Renault gearbox where the gearbox was in front of the engine,? That turned around would have you heading in the right direction. Renault 5 comes to mind, as well as the Renault Feugo . Its the same problem though in that the input into the box is opposite to what it was designed to take. The thrust loads exerted by the helical gears are reversed and acting axially in the opposite direction. So instead of the thrust force acting against a sizable bearing its acting against a lesser sized shoulder. Now how much pressure is actually applied I'm not sure- the formula I have found is a bit too much for my brain to be fun. It cant be a HUGE amount because surely that means the engines power is being robbed generating a load of heat. Here's 5th gear for example...  I have marked the new rotation direction produced by the goldwing engine. Normally the driver gear is turning anti clockwise and so trying to force the driven gear downwards against this thrust surface...  But now it being driven in an opposite direction it wants to ride up against the syncro hub...  Now the thrust surface would be that outer needle bearing shell edge running against the hub. Is it enough? Can I machine the hub out ( hardened!!!) and fit a thrust washer? Or a 3 part thrust bearing? Or do I fill it full of banana skins and get back on with the engine build? This one wont see such high loads being 5th gear anyway. Really good oil with a dash of hopes and dreams and a snippet of wishful thinking might just be enough? Until I strip the box down further to look at the other clusters I can't make my mind up Here's some lovely diagrams you can ponder ...   |
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